function random(number){
    return Math.floor(Math.random()*(number+1));
}

function bgChange(){
    const ranCol=`rgb(${random(255)},${random(255)},${random(255)})`
    document.body.style.backgroundColor =ranCol
}

/**@type{HTMLButtonElement} */
let btn2=document.querySelector(".btn2");
btn2.onclick

let btn3=document.querySelector(".btn3")
btn3.addEventListener("click",bgChange)
btn3.removeEventListener("click",bgChange)